Efforts to biofortify maize with provitamin A carotenoids have been successful, but the impact on vitamin A (VA) status has not been determined. We conducted two studies that investigated the bioefficacy of provitamin A carotenoids from maize and compared maize percentage and carotenoid concentrations on VA status in VA-depleted Mongolian gerbils (Meriones unguiculatus). Gerbils (n = 40/study) were fed a white maize diet 4 wk prior to treatment. In study 1, treatments (n = 10/group) included oil control, 60% high-β-carotene maize, and β-carotene or VA supplements (matched to high-β-carotene maize). In study 2, gerbils were fed 30 or 60% orange or yellow maize diets. Gerbils were killed after 4 wk. In study 1, liver VA concentrations, compared with the high-β-carotene maize group (0.25 ± 0.15 μmol/g), were higher in the VA group (0.56 ± 0.15 μmol/g, P < 0.05), lower in the control (0.10 ± 0.04 μmol/g, P < 0.05), and did not differ in the β-carotene group (0.25 ± 0.08 μmol/g). Bioconversion was ∼3 μg β-carotene to 1 μg retinol (1.5 mol β-carotene to 1 mol retinol). The liver β-carotene content was greater in the high-β-carotene maize group (26.4 ± 6.0 nmol) than in the β-carotene supplement group (14.1 ± 6.0 nmol; P < 0.05). In study 2, the gerbils' VA status improved with increasing dietary β-carotene. Liver VA in gerbils fed orange maize was greater than in those fed yellow maize, regardless of maize percentage (P < 0.05). Biofortified maize adequately maintained VA status in Mongolian gerbils and was as efficacious as β-carotene supplementation. In populations consuming maize as a staple food, using orange instead of white maize could dramatically affect VA status.

Farmers, scientists, and other soil health stakeholders require interpretable indicators of soil hydraulic function. Determining which indicators to use has been difficult because of measurement disconformity, spatial and temporal variability, recently established treatments, and the effect of site characteristics on management practice differences. The North American Project to Evaluate Soil Health Measurements includes 124 sites uniformly sampled across a range of soil health management practices in North America in 2019. We compare and recommend indicators of hydraulic function that best characterize soil health. We assessed the relationship of each indicator to a suite of soil inherent properties and climate variables, the response of each indicator to soil health management practices, the effect that soil inherent properties (clay content, sand content, and pH) and climatic variables (10‐yr mean annual precipitation and temperature) had on response to management practices, and the relationship among the responses of the indicators to soil health management practices. Field capacity measured on intact cores (θ _{FC_INTACT} ) was the best measure of soil hydraulic function, because it responded to management, represents a direct measure of soil hydraulic function, is proximal to stakeholder values, and its response to management was not significantly influenced by inherent and climatic variables. Other suitable indicators are bulk density, soil organic carbon (SOC), and aggregate stability, which are not direct measures of soil hydraulic function but do respond to management and may be practical in situations in which measuring θ _{FC_INTACT} is not. This study informs selection of soil health indicators to measure soil hydraulic function.

Currently accepted pedotransfer functions show negligible effect of management‐induced changes to soil organic carbon (SOC) on plant available water holding capacity (θ _AWHC ), while some studies show the ability to substantially increase θ _AWHC through management. The Soil Health Institute's North America Project to Evaluate Soil Health Measurements measured water content at field capacity using intact soil cores across 124 long‐term research sites that contained increases in SOC as a result of management treatments such as reduced tillage and cover cropping. Pedotransfer functions were created for volumetric water content at field capacity (θ _FC ) and permanent wilting point (θ _PWP ). New pedotransfer functions had predictions of θ _AWHC that were similarly accurate compared with Saxton and Rawls when tested on samples from the National Soil Characterization database. Further, the new pedotransfer functions showed substantial effects of soil calcareousness and SOC on θ _AWHC . For an increase in SOC of 10 g kg ^–1 (1%) in noncalcareous soils, an average increase in θ _AWHC of 3.0 mm 100 mm ^–1 soil (0.03 m ³ m ^–3 ) on average across all soil texture classes was found. This SOC related increase in θ _AWHC is about double previous estimates. Calcareous soils had an increase in θ _AWHC of 1.2 mm 100 mm ^–1 soil associated with a 10 g kg ^–1 increase in SOC, across all soil texture classes. New equations can aid in quantifying benefits of soil management practices that increase SOC and can be used to model the effect of changes in management on drought resilience.